1. Technical Field
The present invention relates to a liquid crystal device suitably used for displaying images, such as letters, numeric characters, and pictures, by controlling the orientation of liquid crystals sealed between a pair of substrates. The present invention also relates to a method for manufacturing the liquid crystal device.
2. Background Art
In general, liquid crystal devices are formed by attaching an illuminating device, such as a backlight, and a liquid crystal-driving IC to a liquid crystal panel. The liquid crystal panel is formed by bonding a pair of substrates formed with electrodes across a sealing section so that the electrodes oppose each other, by sealing liquid crystal in a cell gap formed between the electrodes, and by bonding polarizers on the outside surfaces of the substrates.
One of the pair of substrates may be provided with a substrate protrusion protruding toward the outer periphery from the other substrate, and a wiring terminal section conductively connected to an electrode formed on the inside surface of the substrate may be formed on the surface of the substrate protrusion. To the wiring terminal section, a liquid crystal-driving IC may be directly mounted, and a conductive connecting member, such as a flexible printed circuit board (FPC), conductively connected to the liquid crystal-driving IC may be mounted.
In a conventional liquid crystal device, a part of the above sealing section for sealing liquid crystal is constituted by an anisotropic conductive material. The anisotropic conductive material is formed by, for example, mixing conductive particles into a medium, such as resin. As the conductive particles, conductive particles such as metal, or synthetic resin particles whose outer surfaces are coated by conductive layers such as plated films, are used.
The anisotropic conductive material constituting a part of the sealing section is used for connecting electrodes formed on the other substrate opposed to the substrate having the substrate protrusion to the wiring terminal section formed on the substrate protrusion.
A sealing material and the anisotropic conductive material are applied on the surface of the substrate, respectively, by printing or the like. Usually, the sealing material is applied on the surface of one substrate, and the anisotropic conductive material is applied on the surface of the other substrate. By bonding the pair of substrates to each other, the sealing material and the anisotropic conductive material are joined to each other to form a one-piece sealing section and arranged so as to surround the liquid crystal. The sealing section must provide a hermetic seal in order to seal in the liquid crystal. Therefore, ends of the sealing material and the ends of the anisotropic conductive material should be formed at positions accurately corresponding to each other.
Thus, in the conventional liquid crystal device, the distance between the ends of the substrates is measured to thereby confirm whether or not the sealing material and the anisotropic conductive material are formed at correct positions. This is very important in reducing the displacement of the sealing material relative to the anisotropic conductive material, and in preventing occurrence of defects in the sealing section, which will be described later.
In addition, in the above conventional liquid crystal device, when the sealing material on one substrate and the anisotropic conductive material on the other substrate are joined to each other when the substrates are bonded to each other, displacement of the sealing material relative to the anisotropic conductive material, and sealing defects due to insufficient sealing material or insufficient anisotropic conductive material may occur in joined areas between the sealing material and the anisotropic conductive material, or air bubbles may become entrapped into the joined areas lowering sealing strength.
On the other hand, in contrast to the above, by the displacement of the sealing material relative to the anisotropic conductive material, or when there is an excess of the sealing material or the anisotropic conductive material, the sealing section in the joined areas may spread to protrude to the inside and the outside. When the sealing section protrudes to the outside of the joined areas due to an excess of the sealing material in this way, in a substrate breaking process to be performed later (a process in which large substrates (base substrates) are bonded to each other to form a plurality of liquid crystal panels at one time, scribe lines are formed on the surface of the large base substrates, and stress is applied along the scribe lines to break the large base substrates), breaking defects may occur when the applied stress is uneven, whereby a broken-off section is formed at a site not along the scribe lines.